Questions to ask contractors in replacing A/C

Old 08-13-08, 10:25 PM
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Questions to ask contractors in replacing A/C

I browsed the forums and didn't find what I was looking for so am hoping someone can help out.

I live in the Phoenix, AZ area and have realized that the Trane a/c unit in my 2100 sq ft tri-level home is 14 years old. It is having a tough time keeping our house cool (thermostat is set at 84 and our a/c runs most of the day & night), and a tech who did a recent tune-up said it will likely go soon. We're reluctant to fork out the big $$ for a new unit, but figure at 14 years old, our Trane will go sometime soon, so why not replace it now with something more efficient and that cools better. So...

What questions should I be asking when getting bids from contractors? I got one bid already ($9600 for a Lennox XP14). He suggested a variable speed 5-ton system but to my knowledge did not make any load calculations (would he have gone around the house to do this? If so, he didn't do it.). He recommended Lennox over Trane, saying they were about the same in quality, but that Trane was more money & the Lennox is quieter (he sells both). Also, the Trane filters emit ozone, which the Lennox filters (MERV-16) don't. No mention of replacing ductwork. Is this something that should be done? Or at least tested? Should contractors test the ductwork before bidding on a job?

Any input on questions to ask as I get bids, comments on best systems (I hear recommendations all over the map -- Trane, Lennox, York, Carrier - the only consistent word seems to be staying away from Goodman), etc. would be appreciated. Thanks!
Old 08-13-08, 10:39 PM
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Hello there!

Regarding the load calculation, in order to properly size a unit, a contractor must do the Manual J heat loss/load calculation. This calculation does entail taking measurements and notes of doors, windows, all rooms, insulation, air infiltration- it is quite comprehensive. If this is not done, you may end up with an undersized struggling unit, or an oversized unit that leaves you feeling cold yet clammy. Not a great thing.

As for filters, the Trane cleaner he was probably talking about is the CleanEffects, which like others in it's category does produce ozone. Honestly, I'd go with a good MERV rated filter/pleated media filter, in lieu of the electrostatic systems. I had an old Honeywell electrostatic with which I removed the innards to install a disposable 5" pleated.

Ductwork should also be checked to verify it is in good standing. I believe there are some calculations that sometimes are used too.

Unit wise, I have heard good things about Trane/American Standard, Lennox, and a few others. I have a KeepRite with which I have had only one 20-40$ repair done DIY style in 10 years. You're going to hear from others that installation can be more important than brand in the end, so make sure you have a good contractor who does the job right. Don't be afraid to ask questions, check BBB, ask friends, etc. With a good installation you will be cool for years.

The higher the SEER unit you choose, the more upfront paid, with lower electrical bills. You have to find a good balance so payback isn't too long.

With refrigerant you have to decide whether you are going to go with an R-22 or R-410a unit. R-22 will still be around for years even though it will be going through phase out stages.

I do also believe the variable speed blower thing is quite good, from what I've heard.

Okay, I think I covered a good bit. I'm sure others will have something to mention too.

Good luck!

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